Cancerous and non-cancerous cells are incubated with silver nanoparticle biotags and then observed by shining a red laser on them.
Gary Braun and Peter Allen/UCSB

While the tech is likely years away from clinical trials, the team hopes it will eventually lead to a microdevice that can predict when prostate cancer will metastasize--which is key, given it is the metastasis throughout the body, not the primary tumor, that kills prostate cancer patients.

"The delay is not well understood," says Gary Braun, biologist and second author of the paper that appears this week in the Proceedings of the National Academy of Sciences. "There is a big focus on understanding what causes the tumor to shed cells into the blood. If you could catch them all, then you could stop metastasis. The first thing is to monitor their appearance."

The team is employing silver nanoparticles to biotag cancerous cells and then observe them using a laser technique called surface enhanced Raman spectroscopy. "Silver nanoparticles emit a rich set of colors when they absorb the laser light," Braun says. "This new technology could be more powerful than fluorescence."

What makes their approach a breakthrough is that by including more markers they are able to identify (and observe) unique tumor cells that are actually different than the main ones, so they can observe changes early on that indicate future metastasis.

"These different cells must be strong enough to start a new tumor, or they must develop changes that allow them to colonize in other areas of the body," says first author Alessia Pallaoro, a post-doc fellow at UCSB's Department of Chemistry and Biochemistry. "Some changes must be on the surface, which is what we are trying to detect."

Pallaoro adds that as they find new biomarkers, this technique can actually be expanded by adding more colors. And by developing a microdevice, they might be able to not only diagnose prostate cancer, but predict metastasis as well.